In Cappadocia more than 50 “underground cities” have been listed. Those “underground cities” are very complex networks including several dozen rooms connected by narrow and long corridors. One of the widest is the famous underground city of Derinkuyu, that includes several levels and slopes down to a depth of 45 m. Despite the impressive dimensions of the network of Derinkuyu, which could probably shelter about 700 to 1000 people, the capacity of most of these underground complexes did not exceed a few hundred people. Therefore, it should be more realistic to call them village underground refuges.
The Cappadocian refuges have got a variety of vital facilities: vent pipes, big and small niches, water wells and grain silos. For the defense, in a few village underground refuges, there are grooves carved in the rock to install wooden doors and narrow passages, but the most characteristic defense system is the stone door, that is a stone disc similar to a millstone. All the “underground cities” of Cappadocia are protected by stone doors, some of them being very impressive in scale. The biggest stone door of the village underground refuge of Özkonak is 1,8 m high and 0,67 m wide, with a total weight of 3,5 tons. The hole located in the center of numerous stone doors was probably used as a loophole. In many Cappadocian refuges, there are also other loopholes pierced in the walls or the ceiling and opening in front of the door. In village underground refuges of Cappadocia, the multiple successive doors and the loopholes offer a complex and very efficient active defense.
Cappadocian village underground refuges were dug by rural communities to protect themselves against Arabian raids (from the 8th to the 10th century) and against the attacks of the Ottomans and the Turkomans (from the 13th to the 15th century).